You Can Perform Untethered iOS 4.2.1 Jailbreak Without Restoring, in Upcoming Redsn0w Version

In a recent conversation with another user on Twitter, MuscleNerd announced that the new version of the Redsn0w jailbreak will run on all devices untethered iOS updated to 4.2.1. The procedure is the same, just run the program, regardless of whether the devices have already been unlocked (jailbreak tethered) with the previous release of Redsn0w or still are in the original firmware.

It means that users who have already tethered to jailbreak firmware 4.2.1 will not be forced to restore the original firmware to their DEVICE, and then run the jailbreak with the new version of Redsn0w, simply you have to download, install and launch the new version of this tool for your DEVICE. It will then perform an “upgrade ” jailbreak from tethered to untethered, without having to reset the device.